* Higher NOx emissions: This leads to failing emissions tests and potentially contributes to air pollution.
* Rough idle: The engine might run rough, especially at idle.
* Poor fuel economy: The engine may run less efficiently.
* Pinging or knocking: The engine might experience detonation (pinging) due to the altered air/fuel mixture.
* Check Engine Light (CEL): This is the most obvious symptom, triggered by the insufficient flow detected by the car's computer.
The insufficient flow can be caused by several issues:
* A clogged EGR valve: Carbon deposits can build up and restrict the flow of exhaust gas. This is a common problem and often requires cleaning or replacement of the valve.
* A faulty EGR valve: The valve itself might be malfunctioning, either failing to open sufficiently or sticking in a partially open position. This usually requires replacement.
* Vacuum leaks: The EGR valve is often controlled by vacuum, and leaks in the vacuum lines can prevent it from operating correctly.
* A clogged EGR passage: The passages in the intake manifold or exhaust system can become blocked, restricting flow even if the valve is functioning properly.
* Problems with the EGR position sensor: This sensor monitors the EGR valve's position and if faulty, may cause incorrect readings leading to the code.
To fix the problem, you'll need to diagnose the underlying cause. This usually involves:
1. Inspecting the EGR valve: Look for carbon buildup and check if it moves freely.
2. Checking vacuum lines: Inspect for leaks or cracks.
3. Testing the EGR valve: This may require specialized tools to measure its operation.
4. Cleaning or replacing the EGR valve: Cleaning is often a first step, but replacement might be necessary if cleaning doesn't solve the problem.
It's generally recommended to have a mechanic diagnose and repair this issue, as improper repair can lead to further engine damage or continued emissions problems. They have the tools and expertise to properly identify the cause of the insufficient flow.
